Polarization variability among Wolf-Rayet stars. VIII - Emission lines versus continuum in WR + O binaries
1993; IOP Publishing; Volume: 413; Linguagem: Inglês
10.1086/173040
ISSN1538-4357
Autores Tópico(s)Astrophysics and Star Formation Studies
Resumoview Abstract Citations (23) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Polarization Variability among Wolf-Rayet Stars. VIII. Emission Lines versus Continuum in WR+O Binaries Moffat, Anthony F. J. ; Piirola, Vilppu Abstract Phase-dependent, linear polarization observations of two noneclipsing WC7 + O binaries (HD 97152 and HD 152270) with periods of about 8 days show that the strongest emission-line complex does not vary significantly in polarization, in contrast to the continuum. In fact, we deduce that there is no phase-dependent intrinsic polarization in the lines, and that for HD 152270 the remaining static polarization shows no evidence for intrinsic polarization beyond that obtained from a simple binary model. This is as expected in WR + O binaries if the orbital polarization modulation is due mainly to scattering of O-companion light off free electrons in a hot dense spherically symmetric WR wind. In such systems, there is little or no asymmetric distribution of free electrons off which WR emission-line and continuum photons can scatter and produce detectable polarization. Similarly but not identically during our 1991 June observations, the peculiar 3.77 day variable WN5 star EZ CMa (HD 50896) shows a small but significant variation in emission-line polarization compared to its large continuum modulation amplitude. However, unlike WR + O binaries, the strong He II 468.6 nm line in EZ CMa does have a small, constant but nonzero intrinsic component of polarization. Publication: The Astrophysical Journal Pub Date: August 1993 DOI: 10.1086/173040 Bibcode: 1993ApJ...413..724M Keywords: Binary Stars; Line Spectra; Polarized Light; Stellar Spectra; Wolf-Rayet Stars; Astronomical Polarimetry; Astronomical Spectroscopy; Emission Spectra; Astrophysics; STARS: WOLF-RAYET; STARS: INDIVIDUAL HENRY DRAPER NUMBER: HD 50896; STARS: INDIVIDUAL HENRY DRAPER NUMBER: HD 97152; STARS: INDIVIDUAL HENRY DRAPER NUMBER: HD 152270; POLARIZATION; STARS: BINARIES: CLOSE full text sources ADS | data products SIMBAD (3) Related Materials (7) Part 1: 1987ApJ...322..870S Part 2: 1987ApJ...322..888D Part 3: 1988ApJ...330..286S Part 4: 1989ApJ...343..902R Part 5: 1989ApJ...347.1034R Part 6: 1990ApJ...359..211R Part 7: 1992ApJ...386..288D
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